United Nations: Defying London and Washington, the United Nations General Assembly (UNGA) has voted to refer to the world court the dispute between Britain and Mauritius over the Chagos Archipelago where the strategic US Indian Ocean military base is located on the Diego Garcia island.

A file photo of the United Nations General Assembly. Reuters

Permanent Representative Syed Akbaruddin said India supported the resolution as "it is a matter of principle for India to uphold the process of decolonisation and the respect for sovereignty of nations."

The resolution asking for a non-binding advisory opinion from the Hague-based International Court Justice (ICJ) on the dispute received the vote of 94 countries while 15 voted against it and 65 abstained.

Britain cut off the Chagos Archipelago from Mauritius in 1965 before granting it independence in 1968.

Britain then leased Diego Garcia to the US, which set up a military base there.

Mauritius maintains that the separation of the archipelago before its independence is illegal and asserts its rights to it.

Since Britain would not agree to the dispute going to the ICJ, which would have made a binding judgment, the UNGA resolution asks for an advisory opinion, which could have moral force affecting public opinion.

The resolution asks the ICJ to provide an advisory opinion if the decolonisation of Mauritius was legally completed because it separated the Chagos Archipelago while giving independence to Mauritius.

It also asks the court about the legal consequences of Britain continuing to administer the archipelago preventing Mauritius from settling its citizens, particularly those of Chagosian origin, on those islands.

While supporting the resolution that was proposed by Congo, India toned down the original opposition to the base that was voiced vehemently in the 1980s by then prime minister Indira Gandhi, who called the base located about 2,000 km away a potential threat to India.

India appeared to acknowledge the changed strategic environment with the rise of China and the piracy threats to navigation in the Indian Ocean, and its own growing defence cooperation with the US.

"India shares with the international community, security concerns relating to the Indian Ocean," Akbaruddin said. "We are conscious of our collective commitment towards ensuring the security and prosperity of our oceanic space."

But he added, "On balance, however, it is a matter of principle for India to uphold the process of decolonisation and the respect for sovereignty of nations."

Both the Organisation of African Unity and the Non Aligned Movement have backed the efforts of Mauritius to gain control of the archipelago.

British Permanent Representative Matthew Rycroft reiterated his country's opposition to the dispute going before a court and said it should be settled through bilateral talks.

US Deputy Permanent Representative Michele Sison said that the Diego Garcia base was critical to regional and global security.

The issue was a bilateral dispute and not a matter of decolonisation, she said, and the ICJ intervention would undermine the court's role in giving advisory opinions.